James Farley
Underwood
11/14/07
D5
Log 4- Making the New from the Old & Fossil Genes: Broken Pieces of Yesterday’s Life
Synopsis:
In the treetops of
Variation enables each species to form a symbiotic environmental relationship. These coincidences found in everyday environments enable scientists to examine the cause and effect by linking fossil evidence with living and real-life common interaction. Only so many things can be understood from fossil records. The speculation is demystified when a living specimen can be observed in its natural environment. Scientists have been able to further their research in these areas through the process of direct observation.
Mutations and genetic variation exist, but these mutations can either be positive, negative, or neutral. There is no guarantee that any of these mutations will show a selective trait in the offspring. The mutation is noted once it becomes visually evidenced in the offspring. Mutations serve as the basis for genetic variation and natural selection.
The evolutionary process consists of three processes consisting of natural selection, sexual selection, and the descent of species with modification. All of these occurrences can be tracked with the study of genetic DNA coding. DNA constitutes the basic building blocks of life. By isolating these genes, scientists can further understand the reasoning behind why things the way they are.
One of the most notable examinations of evidence of genetic variations is the study of light perceived through the color spectrum. It is a proven fact that different animals see different forms of light based on the specific boundaries of their own spectrum limits. Seeing different colors in the spectrum is based on wavelength that the visual capacity of the organism is accustomed to. There is a set of molecules called chromophore and a protein called opsin. Pigments found in the retina of the eye absorb and control light intake. A Homosapiens mix of color consists of violet, blue, green and yellow. In addition, it is important to note that the point at which the greatest capacity of light in the spectrum is reached is called the absorption maximum.
Humans share a relation with chimps in that each shares common opsin for breaking down and absorbing light. SWS, MWS, and LWS serve as the visual factors for determining what is seen. Humans also have a fourth pigment known as rhodopsin. Rhodopsin allows an individual to see in dim light settings. Variations in wavelength are dependent on the individual’s ability and genetic makeup.
One of the main reasons that variations arise and mutations become virtually impossible to reverse is because of gene duplication. In the process of gene duplication, “an existing gene is duplicated, and then the ‘new’ and ‘old’ gene go their separate ways, evolving into distinct genes with separate functions” (Caroll). Thus, certain genes become eliminated over time. According to evolutionary theory, if the scientist traces lineage between ancestors backwards, he/she can find the similarities between those who have branched off in an offspring.
The magnitude of mapping DNA and gene sequences is massive. As such, measures have been developed and practiced in order to manage vast amounts of data. The methodology of categorizing this DNA has been segmented and divided for greater organizational capacity. Some segments of DNA are easier to organize than others. In addition, “particular chunks of junk DNA, called long interspersed elements (LINES) and short interspersed elements (SINES), are very easy to detect”(Caroll). Documenting these elements is just the beginning to grasping the larger concept of life. By tracing similarities found in variational mutations, it is possible to determine similarities between existing species.
From various studies, it was determined that “Old World” apes and have “trichromatic color vision and three cone opsin genes, while the New World monkeys, as well as rodents and other mammals, generally have dichromatic vision and two opsin genes”(Caroll). From the evidence and experiments conducted, it can be surmised that full color vision was developed somewhere after the New/Old World primate division took place. Science is still determining exactly where the split took place, but it is nevertheless beneficial to examine the cause and effect of divergence of full-color ordination in the color spectrum.
Adaption to the color spectrum varies. Many species need specific characteristics and traits to survive, especially in extreme environments. In the ocean and the sea, a greater sensitivity to picking up light is needed in darker areas. Dark-water aquatic dwelling animals are accustomed to blue light at 480nm. Over time, the fish living under 200 meters adapted in order to see and navigate their surroundings.
Sexual selection is just as important a process as natural selection. The male and female parent’s traits make up the genetic prospects and advantages of the selective process. Sexual selection is the pre-emptive process through which natural selection later occurs. The fittest genes characteristic of the parents are passed down to the offspring. When the offspring mate, the new characteristics are passed even further. Eventually, certain undesirable traits will be naturally lost in the offspring while the fit traits take their place. The genes that are lost in the process are known as fossil genes.
Fossil genes can be used to trace back in time and get an idea of how life existed long ago. Over time, the fossil genes decay. When the fossil genes decay, gaps in the DNA strand begin to form. Due to the fact that these gaps are missing, the gene becomes useless because it is no longer able to copy with gaps in it. The fit genes are intact and therefore, fully retain their qualities while the fossil genes decay.
Most of the time, disruptive mutations are purged by the competitive process of natural selection because individuals and offspring bearing them are less fit. But when a trait is no longer under selection, in this case because of a shift in habitat, the genes that were essential in one life style can become dispensable, and mutations can accumulate in them. (Caroll)
If there is no pressure, an organism in a changing environment will most likely not go through natural selection. All in all, the process of selection requires time and chance to be successful. The equations and sequences are endless. In most cases, the genetic duplication fosters the desirable traits in the natural selection process. The genes that are fit get passed on and the genes which are undesirable for survival become fossil genes. Genetic mutations and variations rely upon the full process of natural selection. Fossil genes are learned and studied extensively. New observations are made from scientific history and currently living forms of species possessing the desirable traits of survival.
Take Away Idea:
There are many similarities within species of the scientific world. Adaption is a process that any inquisitive and scholarly mind can grasp. How things adapt, however, is a much deeper and larger thought. The scientific community is only beginning to touch the surface of DNA and the genetic code. More and more similarities are being found and noted. As time progresses, I will hopefully be able to make more connections in order to understand the magnitude and glory of God and all that holds the universe together.
Challenging Concepts:
There was one major concept that I felt was particularly difficult to understand. The pigments and learning the different names of the different proteins that went into producing vision existing within the color spectrum made it hard to grasp the reading. I knew what the author was saying; it just took me awhile to rap my head around the terms. Overall, after some time and rereading, I understood the chapter and was able to grasp the concept at hand. Everything else in the reading was fine and I enjoyed learning a lot about how the visual spectrum works.
Seminar Question:
Through scientific research, can the vision of a human subject be manipulated by genetically enhancing or altering the proteins found in the eye?
Aesthetic Awareness:
We must all be aware of the world around us. If one is not aware, then life will pass them by. It is often that the smallest things in life hold the most meaning. Color and pigmentation of sight is fascinating. Different proteins produce different abilities to see wave length. Scientists must be aware to determine and manipulate the subject they are working with to test their hypothesis. In the case of the book, observation was one of the most essential forms of being aesthetically aware. Scientists had to use their visual skills to document and view their surroundings. Observing different pigments and visual forms of light would not have been possible without visual interpretation. The thought process may be there, but it is lacking without the visual aid to guide and accompany it.
Critical Thinking:
Each of the individuals observing the forms of life had to go beyond the sheer visual capacity of “what meets the eye”. The obvious fact was that mutation took place and most definitely occurred. The evidence of the mutational variation was then found in the study of each specimen that had survived through the process of natural selection. By critically thinking, I discovered that genetic mutation removed the “outdated” and weak genes and replaced them fit genes to be passed down to the offspring of a new generation. The full process of seeing physical evidence for natural selection and survival of the fittest through desirable genetic inheritance bridged the gap of my understanding in explaining the big picture behind adaption. Adaption became a practical real-life understanding for me rather than a dull and dry textbook theory.
Connection:
Chapter three talked about
Vocabulary:
Rhodopsin- pigment in humans which enables them to see in dim light
Gene duplication- an existing gene is duplicated and the “new” and “old” gene go their separate ways
Fossil genes- genes predicted to evolve as a consequence of the continuing action of mutation, over time, in the absence of natural selection
Key Concepts:
-There is more than one way at looking at things: the various color spectrums and wavelengths showed me that there are multiple perspectives to seeing and experiencing life from different angles
-Looking back in time: by looking back in time with fossil evidence, more is understood about life in the past and how it relates to us today
- Advancement as a process of life: those species who adapt to fit the demands of their environment will survive. In collegiate competition, I am constantly adapting to meet the challenges presented before me in order to get good grades and eventually succeed in the professional world.
Bibliography
The Making of the Fittest: DNA and the Ultimate Forensic Record of Evolution by Sean Carroll, W.W. Norton; Reprint edition (September 10, 2007)